From: David Steele <david@pgmasters.net>
To: Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Add basic tests for the low-level backup method.
Date: Sat, 11 Nov 2023 15:21:12 -0400
Message-ID: <03e4cf19-fb76-4891-accc-edd429a25b21@pgmasters.net> (raw)
Hackers,
As promised in [1], attached are some basic tests for the low-level
backup method.
There are currently no tests for the low-level backup method.
pg_backup_start() and pg_backup_stop() are called but not exercised in
any real fashion.
There is a lot more that can be done, but this at least supplies some
basic tests and provides a place for future improvement.
Regards,
-David
[1]
https://www.postgresql.org/message-id/2daf8adc-8db7-4204-a7f2-a7e94e2bfa4b%40pgmasters.netAttachments:low-level-backup-test-v1.patch (text/plain, 4.7K) download
From b1a10ab4ab912e6f174206fcb8ce67496f93df83 Mon Sep 17 00:00:00 2001
From: David Steele <david@pgmasters.net>
Date: Sat, 11 Nov 2023 19:12:49 +0000
Subject: Add basic tests for the low-level backup method.
There are currently no tests for the low-level backup method. pg_backup_start()
and pg_backup_stop() are called but not exercised in any real fashion.
There is a lot more that can be done, but this at least provides some basic
tests and provides a place for future improvement.
---
src/test/recovery/t/040_low_level_backup.pl | 101 ++++++++++++++++++++
1 file changed, 101 insertions(+)
create mode 100644 src/test/recovery/t/040_low_level_backup.pl
diff --git a/src/test/recovery/t/040_low_level_backup.pl b/src/test/recovery/t/040_low_level_backup.plnew file mode 100644index 00000000000..3f30cb6b59c--- /dev/null+++ b/src/test/recovery/t/040_low_level_backup.pl@@ -0,0 +1,101 @@++# Copyright (c) 2023, PostgreSQL Global Development Group++# Test low-level backup method by using pg_backup_start() and pg_backup_stop()+# to create backups.++use strict;+use warnings;++use File::Copy qw(copy);+use File::Path qw(remove_tree);+use PostgreSQL::Test::Cluster;+use PostgreSQL::Test::Utils;+use Test::More;++# Start primary node with archiving+my $node_primary = PostgreSQL::Test::Cluster->new('primary');+$node_primary->init(has_archiving => 1, allows_streaming => 1);+$node_primary->start;++# Start backup+my $backup_name = 'backup1';+my $psql = $node_primary->background_psql('postgres');++$psql->query_safe("SET client_min_messages TO WARNING");+$psql->set_query_timer_restart();+$psql->query_safe("select pg_backup_start('test label')");++# Copy files+my $backup_dir = $node_primary->backup_dir() . '/' . $backup_name;++PostgreSQL::Test::RecursiveCopy::copypath(+ $node_primary->data_dir(), $backup_dir);++# Cleanup files/paths that should not be in the backup. Also remove pg_control+# because it needs to be copied later and it will be obvious if the copy fails.+unlink("$backup_dir/postmaster.pid")+ or BAIL_OUT("unable to unlink $backup_dir/postmaster.pid");+unlink("$backup_dir/postmaster.opts")+ or BAIL_OUT("unable to unlink $backup_dir/postmaster.opts");+unlink("$backup_dir/global/pg_control")+ or BAIL_OUT("unable to unlink $backup_dir/global/pg_control");++remove_tree("$backup_dir/pg_wal", {keep_root => 1})+ or BAIL_OUT("unable to unlink contents of $backup_dir/pg_wal");++# Create a table that will be used to verify that recovery started at the+# correct location, rather than the location recorded in pg_control+$psql->query_safe("create table canary (id int)");++# Advance the checkpoint location in pg_control past the location where the+# backup started. Switch the WAL to make it really obvious that the location+# is different and to put the checkpoint in a new WAL segment.+$psql->query_safe("select pg_switch_wal()");+$psql->query_safe("checkpoint");++# Copy pg_control last so it contains the new checkpoint+copy($node_primary->data_dir() . '/global/pg_control',+ "$backup_dir/global/pg_control")+ or BAIL_OUT("unable to copy global/pg_control");++# Stop backup and get backup_label+my $backup_label = $psql->query_safe("select labelfile from pg_backup_stop()");++# Rather than writing out backup_label, try to recover the backup without+# backup_label to demonstrate that recovery will not work correctly without it,+# i.e. the canary table will be missing and the cluster will be corrupt. Provide+# only the WAL segment that recovery will think it needs.+#+# The point of this test is to explicitly demonstrate that backup_label is+# being used in a later test to get the correct recovery info.+my $node_replica = PostgreSQL::Test::Cluster->new('replica_fail');+$node_replica->init_from_backup($node_primary, $backup_name);+my $canary_query = "select count(*) from pg_class where relname = 'canary'";++copy($node_primary->archive_dir() . '/000000010000000000000003',+ $node_replica->data_dir() . '/pg_wal/000000010000000000000003')+ or BAIL_OUT("unable to copy 000000010000000000000003");++$node_replica->start;++ok($node_replica->safe_psql('postgres', $canary_query) == 0,+ 'canary is missing');++$node_replica->teardown_node();+$node_replica->clean_node();++# Save backup_label into the backup directory and recover using the primary's+# archive. This time recovery will succeed and the canary table will be+# present.+append_to_file("$backup_dir/backup_label", $backup_label);++$node_replica = PostgreSQL::Test::Cluster->new('replica_success');+$node_replica->init_from_backup($node_primary, $backup_name,+ has_restoring => 1);+$node_replica->start;++ok($node_replica->safe_psql('postgres', $canary_query) == 1,+ 'canary is present');++done_testing();--
2.34.1
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To: pgsql-hackers@postgresql.org
Cc: david@pgmasters.net
Subject: Re: Add basic tests for the low-level backup method.
In-Reply-To: <03e4cf19-fb76-4891-accc-edd429a25b21@pgmasters.net>
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